Sheet feeding apparatus and sheet separating apparatus

ABSTRACT

Provided is a sheet folding apparatus including: a stacking unit configured to be stacked with a paper stack; a feeding roller configured to come into contact with a surface of the uppermost sheet of the paper stack and feed sheets in a feeding direction; and a sheet separating mechanism configured to separate the uppermost sheet of the paper stack from the remaining sheets. The sheet separating mechanism has a suction unit that sucks and pulls the uppermost sheet of the paper stack upward in upstream in a feeding direction and an injection mechanism that separates the uppermost sheet from the remaining sheets by injecting air toward a predetermined region including an end face in upstream in the feeding direction of the paper stack including the uppermost sheet. The injection mechanism has a rotary injection unit configured to inject air to change a first injection direction oriented to the predetermined region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on Japanese Patent Application No. 2022-085499filed on May 25, 2022, and Japanese Patent Application No. 2023-075650filed on May 1, 2023, the contents of which are incorporated herein byreference in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a sheet feeding apparatus and a sheetseparating apparatus.

2. Description of Related Art

Conventionally, an apparatus that injects air toward a sheet bundlestacked on a tray to separate sheets from each other and sucks andtransports the uppermost sheet by a suction transport belt is known (seeJapanese Patent No. 3521639, for example).

In Japanese Patent No. 3521639, a pair of air nozzles arranged on theside face side of the sheet bundle inject air to the sheet bundle tofacilitate separation between sheets.

In Japanese Patent No. 3521639, however, it is required to provide apair of air nozzles for facilitating separation between the sheets ofthe sheet bundle stacked on the tray. Further, in Japanese Patent No.3521639, it is required to provide a position detection unit fordetecting the position of the uppermost sheet of the sheet bundle and amechanism for moving the air nozzle in accordance with the detectedsheet position to match the position thereof to the position of theuppermost sheet. Thus, in Japanese Patent No. 3521639, a complexmechanism is required for facilitating separation between sheets, andthis increases the manufacturing cost.

BRIEF SUMMARY

The present disclosure has been made in view of such circumstances andintends to provide a sheet feeding apparatus and a sheet separatingapparatus that can prevent an increase in manufacturing cost andreliably separate and feed the uppermost sheet of a paper stack by usinga simple mechanism.

A sheet feeding apparatus according to a first aspect of the presentdisclosure includes: a stacking unit configured to be stacked with apaper stack including a plurality of sheets; a feeding unit configuredto come into contact with a surface of the uppermost sheet of the paperstack and feed the uppermost sheet in a feeding direction; and a sheetseparating mechanism configured to separate the uppermost sheet of thepaper stack from the remaining sheets, and the sheet separatingmechanism comprises a suction unit configured to suck and pull theuppermost sheet of the paper stack upward in the upstream in the feedingdirection, and an injection mechanism configured to inject air toward apredetermined region including an end face in the upstream in thefeeding direction of the paper stack including the uppermost sheet ofthe paper stack to separate the uppermost sheet from the remainingsheets, and the injection mechanism has a first injection unitconfigured to inject air so as to change a first injection directionoriented to the predetermined region.

According to the sheet feeding apparatus of the first aspect of thepresent disclosure, the uppermost sheet of the paper stack stacked onthe stacking unit is pulled upward by the suction unit in the upstreamin the feeding direction of the sheets. The injection mechanism of thesheet separating mechanism then injects air toward a predeterminedregion including the end face in the upstream in the feeding directionof the paper stack including the uppermost sheet of the paper stack, andthereby the uppermost sheet is separated from the remaining sheets. Insuch a way, according to the sheet feeding apparatus of the first aspectof the present disclosure, it is possible to prevent an increase inmanufacturing cost and reliably separate and feed the uppermost sheet ofa paper stack by using a simple mechanism.

In a sheet feeding apparatus according to a second aspect of the presentdisclosure, in the first aspect, the first injection unit has a nozzleportion that is formed in a cylindrical shape extending along an axisintersecting the height direction of the paper stack and having a closedtip and has an injection hole for injecting air toward the predeterminedregion formed in a side face of the nozzle portion, and a rotary portionconfigured to rotate the nozzle portion in a predetermined directionabout the axis, and air injected from the injection hole is supplied toan internal space of the nozzle portion.

According to the sheet feeding apparatus of the second aspect of thepresent disclosure, it is possible to periodically change, in the heightdirection of the paper stack, the first injection direction of airdirected to a predetermined region of the end face in the upstream inthe feeding direction of the paper stack by using a relatively simplestructure in which the rotary portion rotates the nozzle portion in apredetermined direction about the axis intersecting the height directionof the paper stack. Further, according to the sheet feeding apparatus ofthe second aspect of the present disclosure, it is possible tofacilitate separation between the uppermost sheet and another sheet byblowing air therebetween even when the uppermost sheet is pulled up bythe suction unit with another sheet being in contact with the uppermostsheet.

In a sheet feeding apparatus according to a third aspect of the presentdisclosure, in the second aspect, the nozzle portion injects air fromthe injection hole within an injection region of an angle less than orequal to 180 degrees on the end face side of the paper stack in acircumferential direction about the axis.

According to the sheet feeding apparatus of the third aspect of thepresent disclosure, since air is injected from the injection hole withinan injection region of an angle less than or equal to 180 degrees on theend face side of the paper stack, it is possible to suitably prevent airfrom being injected in a region on the end face side of the paper stackto which no air is injected.

In a sheet feeding apparatus according to a fourth aspect of the presentdisclosure, in the third aspect, the first injection unit has a bodythat holds the nozzle portion, the body has an accommodation hole and asupply path, the accommodation hole accommodates the nozzle portion suchthat a part of the side face in which the injection hole is formedprotrudes, and the supply path communicates with the accommodation holeand is externally supplied with air, and in the nozzle portion, anopening communicating between the supply path and the internal spacewithin a region of an angle less than or equal to 180 degrees in thecircumferential direction is formed at a position facing the supply pathof the side face.

According to the sheet feeding apparatus of the fourth aspect of thepresent disclosure, air is supplied to the internal space of the nozzleportion from the supply path when the opening passes by a positionfacing the supply path, and the air is injected from the injection holeby supplying air from a supply unit to the supply path. Since theopening is formed in a region of an angle less than or equal to 180degrees in the circumferential direction on the side face of the nozzleportion at a position facing the supply path, a period in which air issupplied from the supply path to the internal space and a period inwhich no air is supplied from the supply path to the internal space areperiodically repeated in accordance with the rotation of the nozzleportion. Accordingly, it is possible to periodically change the firstinjection direction of the air directed to the predetermined region.

In a sheet feeding apparatus according to a fifth aspect of the presentdisclosure, in any one of the first aspect to the fourth aspect, therotary portion generates driving force for rotation about the axis byexternally supplied air.

According to the sheet feeding apparatus of the fifth aspect of thepresent disclosure, it is possible to obtain driving force for drivingthe rotary portion by using the air supplied from the supply unitwithout using a dedicated device for generating driving force fordriving the rotary portion.

In a sheet feeding apparatus according to a sixth aspect of the presentdisclosure, in any one of the first aspect to the fifth aspect, thesheet separating mechanism has a second injection unit configured to fixa second injection direction oriented to the predetermined region andinject air.

According to the sheet feeding apparatus of the sixth aspect of thepresent disclosure, since the sheet feeding apparatus has the secondinjection unit configured to fix a second injection direction orientedto the predetermined region and injects air, it is possible tofacilitate separation between the uppermost sheet and another sheet bythe first injection unit and ensure a sufficient volume of air to beblown to the downstream in the feeding direction of the sheets along thesecond injection direction by the second injection unit and reliablyblow the air to a gap formed between the sheets.

A sheet separating apparatus according to a seventh aspect of thepresent disclosure injects air toward a predetermined region of an endface of a paper stack including a plurality of sheets to separate thesheets from each other and includes a nozzle portion that is formed in acylindrical shape extending along an axis intersecting the heightdirection of the paper stack and having a closed tip and has aninjection hole for injecting air toward the predetermined region formedin a side face of the nozzle portion; and a rotary portion configured torotate the nozzle portion in a predetermined direction about the axis,and air injected from the injection hole is supplied to an internalspace of the nozzle portion.

According to the sheet separating apparatus of the seventh aspect of thepresent disclosure, it is possible to periodically change, in the heightdirection of the paper stack, the first injection direction of airdirected to a predetermined region of the end face in the upstream inthe feeding direction of the paper stack by using a relatively simplestructure in which the rotary portion rotates the nozzle portion in apredetermined direction about the axis intersecting the height directionof the paper stack. Further, according to the sheet separating apparatusof the seventh aspect of the present disclosure, it is possible tofacilitate separation between the uppermost sheet and another sheet byblowing air therebetween even when the uppermost sheet is pulled up bythe suction unit with another sheet being in contact with the uppermostsheet.

In a sheet separating apparatus according to an eighth aspect of thepresent disclosure, in the seventh aspect, the nozzle portion injectsthe air from the injection hole within an injection region of an angleless than or equal to 180 degrees on the end face side of the paperstack in a circumferential direction about the axis.

According to the sheet separating apparatus of the eighth aspect of thepresent disclosure, since air is injected from the injection hole withinan injection region of an angle less than or equal to 180 degrees on theend face side of the paper stack, it is possible to suitably prevent airfrom being injected in a region on the end face side of the paper stackto which no air is injected.

A sheet separating apparatus according to a ninth aspect of the presentdisclosure, in the eighth aspect, has a body that holds the nozzleportion, the body has an accommodation hole and a supply path, theaccommodation hole accommodates the nozzle portion such that a part ofthe side face in which the injection hole is formed protrudes, and thesupply path communicates with the accommodation hole and is externallysupplied with air, and in the nozzle portion, an opening communicatingbetween the supply path and the internal space within a region of anangle less than or equal to 180 degrees in the circumferential directionis formed at a position facing the supply path of the side face.

According to the sheet separating apparatus of the ninth aspect of thepresent disclosure, air is supplied to the internal space of the nozzleportion from the supply path when the opening passes by a positionfacing the supply path, and the air is injected from the injection holeby supplying air from a supply unit to the supply path. Since theopening is formed in a region of an angle less than or equal to 180degrees in the circumferential direction on the side face of the nozzleportion at a position facing the supply path, a period in which air issupplied from the supply path to the internal space and a period inwhich no air is supplied from the supply path to the internal space areperiodically repeated in accordance with the rotation of the nozzleportion. This makes it possible to periodically change the firstinjection direction of the air directed to the predetermined region.

A sheet separating apparatus according to a tenth aspect of the presentdisclosure, in any one of the seventh aspect to the ninth aspect, therotary portion generates driving force for rotation about the axis byexternally supplied air.

According to the sheet separating apparatus of the tenth aspect of thepresent disclosure, it is possible to obtain driving force for drivingthe rotary portion by using the air supplied from the supply unitwithout using a dedicated device for generating driving force fordriving the rotary portion.

According to the present disclosure, it is possible to provide a sheetfeeding apparatus and a sheet separating apparatus that can prevent anincrease in manufacturing cost and reliably separate and feed theuppermost sheet of a paper stack by using a simple mechanism.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a front view illustrating a sheet folding apparatus accordingto a first embodiment of the present disclosure.

FIG. 2 is a perspective view illustrating a feeding roller and a sheetseparating mechanism illustrated in FIG. 1 .

FIG. 3 is a diagram of the sheet separating mechanism illustrated inFIG. 1 when viewed from the feeding roller side, which illustrates astate before a suction unit pulls a sheet upwards.

FIG. 4 is a diagram of the sheet separating mechanism illustrated inFIG. 1 when viewed from the feeding roller side, which illustrates astate after the suction unit has pulled the sheet upwards.

FIG. 5 is a sectional view of the sheet separating mechanism illustratedin FIG. 3 when viewed from the arrow direction of the line A-A.

FIG. 6 is a sectional view of the sheet separating mechanism illustratedin FIG. 4 when viewed from the arrow direction of the line B-B.

FIG. 7 is a sectional view of the sheet separating mechanism illustratedin FIG. 4 when viewed from the arrow direction of the line C-C.

FIG. 8 is a perspective view of a rotary injection unit illustrated inFIG. 3 .

FIG. 9 is a partial sectional view of the rotary injection unitillustrated in FIG. 8 .

FIG. 10 is a diagram of the rotary injection unit illustrated in FIG. 8when viewed along an axis of a nozzle portion.

FIG. 11 is a sectional view of the rotary injection unit illustrated inFIG. 9 when viewed from the arrow direction of the line D-D.

FIG. 12 is a perspective view illustrating a feeding roller and a sheetseparating mechanism of a sheet folding apparatus according to a secondembodiment of the present disclosure.

FIG. 13 is a diagram of the sheet separating mechanism illustrated inFIG. 12 when viewed from the feeding roller side, which illustrates astate before a suction unit pulls a sheet upwards.

FIG. 14 is a perspective view of a rotary injection unit of a thirdembodiment of the present disclosure.

FIG. 15 is a partial sectional view of the rotary injection unit of thethird embodiment of the present disclosure.

DETAILED DESCRIPTION First Embodiment

A sheet folding apparatus (sheet feeding apparatus) 100 according to afirst embodiment of the present disclosure will be described withreference to the drawings. FIG. 1 is a front view illustrating the sheetfolding apparatus 100 according to one embodiment of the presentdisclosure. As illustrated in FIG. 1 , the sheet folding apparatus 100of the present embodiment includes a stacking unit 10, a feeding roller(sheet feeding portion) 20, a sheet separating mechanism (sheetseparating apparatus) 30, a conveyor belt 40, a sheet folding unit 50,and a control unit 60.

While the sheet folding apparatus 100 including the conveyor belt 40 andthe sheet folding unit 50 is described in the present embodiment, othersheet feeding apparatuses not having the conveyor belt 40 and the sheetfolding unit 50 may be employed. In such a case, the sheet feedingapparatus includes the stacking unit 10, the feeding roller 20, and thesheet separating mechanism 30.

The stacking unit 10 is a device that is stacked with a paper stack Sincluding a plurality of sheets P. The paper stack S is formed of theplurality of sheets P stacked on a shelf 11 in a height direction HD.The shelf 11 is moved along the height direction HD by a lift mechanism12 so that the uppermost sheet P of the paper stack S comes close to thefeeding roller 20.

The feeding roller 20 is a device that comes into contact with thesurface of the uppermost sheet P of the paper stack S and feeds thesheet P in the feeding direction FD. The feeding roller 20 is rotated inthe rotation direction RD about an axis Xf extending in the horizontaldirection, moves the uppermost sheet P of the paper stack S along thefeeding direction FD by frictional force, and thereby feeds the sheet Pto the conveyor belt 40. Note that a feeding belt that feeds the sheet Pby using an endless belt may be employed instead of the feeding roller20.

The sheet separating mechanism 30 is an apparatus that separates theuppermost sheet P of the paper stack S from the remaining sheets P.Details of the sheet separating mechanism 30 will be described later.

The conveyor belt 40 is a device that feeds the sheet P fed from thefeeding roller 20 to the sheet folding unit 50. The conveyor belt 40 hasa transport belt 41 and a pair of rollers 42 between which the transportbelt 41 is stretched. The conveyor belt 40 drives the transport belt 41through the pair of rollers 42 and transports the sheet P fed to thetransport belt 41 to the sheet folding unit 50 along the feedingdirection FD. Arrows illustrated on the pair of rollers 42 illustratethe rotation direction of the pair of the roller 42.

The sheet folding unit 50 is a device that folds, into two, the sheet Pfed from the conveyor belt 40. The sheet folding unit 50 has a buckle 51formed of a pair of rails 51 a, 51 b, a stopper 52, a pair of intakerollers 53, 54 and a folding roller 55. Arrows illustrated on the pairof intake rollers 53, 54, and the folding roller 55 illustrate rotationdirections of respective rollers. The sheet folding unit 50 feeds, bythe pair of intake rollers 53, 54, the sheet P fed from the conveyorbelt 40 and introduces the sheet P from a slot 51 c of the buckle 51 toa clearance 51 d between the pair of rails 51 a, 51 b.

As illustrated in FIG. 1 , when the pair of intake rollers 53, 54introduces the sheet P to the clearance 51 d and feeds the sheet Ptoward the stopper 52, the leading edge of the sheet P then comes intocontact with the stopper 52. When the pair of intake rollers 53, 54further press the sheet P in the feeding direction FD after the leadingedge of the sheet P has come into contact with the stopper 52, the sheetP is folded downstream in the feeding direction FD. The folded sheet Pis fed downward by the intake roller 53 and the folding roller 55 with afolded portion Pf being the leading edge.

The control unit 60 is a device that controls respective units of thesheet folding apparatus 100. The control unit 60 controls respectiveunits of the sheet folding apparatus 100 by reading a control programstored in a storage unit (not illustrated) and executing the controlprogram.

Next, details of the sheet separating mechanism 30 will be describedwith reference to the drawings. FIG. 2 is a perspective viewillustrating the feeding roller 20 and the sheet separating mechanism 30illustrated in FIG. 1 . FIG. 3 is a diagram of the sheet separatingmechanism 30 illustrated in FIG. 1 when viewed from the feeding roller20 side, which illustrates a state before a suction unit 31 pulls thesheet P upwards. FIG. 4 is a diagram of the sheet separating mechanism30 illustrated in FIG. 1 when viewed from the feeding roller 20 side,which illustrates a state after the suction unit 31 has pulled the sheetP upwards. In FIG. 3 and FIG. 4 , illustration of the sheet P isomitted. As illustrated in FIG. 2 to FIG. 4 , the sheet separatingmechanism 30 has the suction unit 31 and an injection mechanism 32.

The suction unit 31 is a device that sucks and pulls upward theuppermost sheet P of the paper stack S in the upstream in the feedingdirection FD of the paper stack S stacked on the stacking unit 10. Thesuction unit 31 is connected to a sucking mechanism (not illustrated)and sucks ambient air from a suction face 31 a to reduce the pressure ofthe upper face region of the sheet P in contact with the suction face 31a into a negative pressure state having a lower pressure than theatmospheric pressure.

The suction unit 31 can be moved along the height direction HD withrespect to a body 30 a of the sheet separating mechanism 30. Once theupper region of the sheet P is in the negative pressure state and thedifference between the negative pressure and the atmospheric pressureexceeds the weight of the suction unit 31, the suction unit 31 suckingthe uppermost sheet P is pulled upward from the paper stack S. Thesuction unit 31 sucks and pulls the uppermost sheet P of the paper stackS upward in such a way and switches the state illustrated in FIG. 3 tothe state illustrated in FIG. 4 .

FIG. 5 is a sectional view of the sheet separating mechanism 30illustrated in FIG. 3 when viewed from the arrow direction of the lineA-A. FIG. 6 is a sectional view of the sheet separating mechanism 30illustrated in FIG. 4 when viewed from the arrow direction of the lineB-B. As illustrated in FIG. 5 , the suction face 31 a of the suctionunit 31 is in contact with the uppermost sheet P of the paper stack S ina state before the suction unit 31 pulls the sheet P upward. Asillustrated in FIG. 5 , in this state, the uppermost sheet P has not yetbeen pulled up from the paper stack S and is stacked without any gapbetween the uppermost sheet P and the remaining sheets P.

As illustrated in FIG. 6 , the suction face 31 a of the suction unit 31is in contact with the uppermost sheet P of the paper stack S in a stateafter the suction unit 31 has pulled the sheet P upward. As illustratedin FIG. 6 , in this state, the uppermost sheet P has been pulled up fromthe paper stack S, and a gap has been provided between the uppermostsheet P and the remaining sheets P stacked on the paper stack S.

The injection mechanism 32 is a mechanism that injects air toward apredetermined region including an end face Se in the upstream in thefeeding direction FD of the paper stack S including the uppermost sheetP of the paper stack S and separates the uppermost sheet P from theremaining sheets P. The injection mechanism 32 separates another sheet Pattached to the uppermost sheet P, which is sucked by the suction unit31, from the uppermost sheet P.

The suction unit 31 illustrated in FIG. 6 separates the uppermost sheetP from the remaining sheets P stacked on the paper stack S by suckingand pulling up the uppermost sheet P in the height direction HD. In FIG.6 , however, the sheets P under the uppermost sheet P are not separatedfrom and is attached to the uppermost sheet P. The injection mechanism32 of the present embodiment guides air to the interface between theuppermost sheet P and another sheet P attached to the underside thereofand thereby separates the uppermost sheet P and another sheet P attachedto the underside thereof from each other.

As illustrated in FIG. 1 to FIG. 4 , the injection mechanism 32 has apair of rotary injection units (first injection units) 33, a pair offixed injection units (second injection units) 34, a switch injectionunit 35, a pair of pressing portions 36, a connection portion 37, and asupply unit 38.

The rotary injection units 33 are devices that inject air so as toperiodically change a first injection direction JD1 oriented to apredetermined region including the end face Se in the upstream in thefeeding direction FD of the paper stack S. The pair of rotary injectionunits 33 are fixed to the body 30 a of the sheet separating mechanism30. As illustrated in FIG. 6 , the rotary injection unit 33 injects airin the first injection direction JD1 in a state where the suction unit31 has pulled the sheet P upward.

The first injection direction JD1 in which the rotary injection units 33inject air is changed along the circumferential direction CD illustratedin FIG. 6 and about an axis Ra extending in the horizontal direction.Further, the rotary injection units 33 change the first injectiondirection JD1 in a region of an angle θ1 illustrated in FIG. 6 . Notethat, while FIG. 6 illustrates an example in which the first injectiondirection JD1 is changed counterclockwise, the first injection directionJD1 may be changed clockwise. The detailed structure of the rotaryinjection unit 33 will be described later.

The fixed injection unit 34 is a device that injects air with a secondinjection direction JD2 being fixed where the second injection directionis a direction oriented to a predetermined region including the end faceSe in the upstream in the feeding direction FD of the paper stack S.FIG. 7 is a sectional view of the sheet separating mechanism 30illustrated in FIG. 4 when viewed from the arrow direction of the lineC-C. The fixed injection unit 34 has a nozzle portion 34 a that injectsthe air supplied from the supply unit 38 along the second injectiondirection JD2 that is the horizontal direction.

The switch injection unit 35 is a device that injects air along a thirdinjection direction JD3 that is the horizontal direction to a spacebelow the uppermost sheet P pulled up by the suction unit 31 in a statewhere the suction unit 31 has pulled the sheet P upward. As illustratedin FIG. 5 , the switch injection unit 35 has a lid portion 35 a that canswing about a swing axis 35 c and an injection hole 35 b that injectsthe air supplied from the supply unit 38.

As illustrated in FIG. 5 , in a state before the suction unit 31 pullsthe sheet P upward, the switch injection unit 35 seals the injectionhole 35 b with the lid portion 35 a so that no air is injected from theinjection hole 35 b. On the other hand, as illustrated in FIG. 6 , in astate after the suction unit 31 has pulled the sheet P upward, theswitch injection unit 35 is switched so that the lid portion 35 a swingsclockwise about the swing axis 35 c and air is injected from theinjection hole 35 b. The lid portion 35 a comes into contact with aprotrusion portion 31 b fixed to the suction unit 31 and thereby swingsclockwise about the swing axis 35 c.

As illustrated in FIG. 2 , the pressing portion 36 is a device thatpresses an end portion in the width direction WD of the uppermost sheetP stacked on the paper stack S so that the end portion is not separatedfrom the paper stack S. The pressing portion 36 can hold the position ofthe sheet P by pressing the end portion in the width direction WD of theuppermost sheet P onto the paper stack S even in a state where theuppermost sheet P has been pulled upward by the suction unit 31 and blowair into a region below the uppermost sheet P to facilitate separationfrom the remaining sheets P.

The connection portion 37 is a device that is formed in a rod shape soas to extend in the horizontal direction and fixes the pair of fixedinjection units 34 and the pair of pressing portions 36 with respect tothe body 30 a of the sheet separating mechanism 30. The connectionportion 37 is fixed to the body 30 a of the sheet separating mechanism30. The positions in the width direction WD of the pair of fixedinjection units 34 and the pair of pressing portions 36 relative to theconnection portion 37 can be adjusted to any positions.

The supply unit 38 is a device that supplies the air to be injected bythe sheet separating mechanism 30. The supply unit 38 supplies therotary injection unit 33 with the air injected by the rotary injectionunit 33 in the first injection direction JD1. Further, the supply unit38 supplies the fixed injection unit 34 with the air injected by thefixed injection unit 34 in the second injection direction JD2. Further,the supply unit 38 supplies the switch injection unit 35 with the airinjected by the switch injection unit 35 in the third injectiondirection JD3 from the injection hole 35 b.

As illustrated in FIG. 6 , the air is injected from the switch injectionunit 35 directed between the uppermost sheet P sucked by the suctionunit 31 and another sheet P underside thereof in the third injectiondirection JD3 that is the horizontal direction. Further, by periodicallychanging the first injection direction JD1 of the air injected from therotary injection unit 33, the air is guided to the gap between theuppermost sheet P and another sheet P underside thereof. The remainingsheets P are separated from the uppermost sheet P by the air injected inthe first injection direction JD1 by the rotary injection unit 33, theair injected in the second injection direction JD2 by the fixedinjection unit 34, and the air injected in the third injection directionJD3 from the injection hole 35 b by the switch injection unit 35described above.

Note that changing the first injection direction JD1 in which the rotaryinjection unit 33 injects air is particularly advantageous inseparating, from the uppermost sheet P, another sheet P attached to theunderside thereof. When adhesion between the uppermost sheet P sucked bythe suction unit 31 and another sheet P attached to the undersidethereof (sheet P illustrated in a dotted line in FIG. 6 ) is large, itmay not be possible to separate, from the uppermost sheet P, anothersheet P attached to the underside thereof by the air injected in thesecond injection direction JD2 by the fixed injection unit 34 or the airinjected in the third injection direction JD3 from the injection hole 35b by the switch injection unit 35. In such a case, it is possible tofacilitate separation between the uppermost sheet P and another sheet Pattached to the underside thereof by changing the first injectiondirection JD1 in which the rotary injection unit 33 injects air.

Next, the detailed structure of the rotary injection unit 33 will bedescribed with reference to FIG. 8 to FIG. 11 . FIG. 8 is a perspectiveview of the rotary injection unit 33 illustrated in FIG. 3 . FIG. 9 is apartial sectional view of the rotary injection unit 33 illustrated inFIG. 8 . FIG. 10 is a diagram of the rotary injection unit 33illustrated in FIG. 8 when viewed along an axis Ra of the nozzle portion33 a. FIG. 11 is a sectional view of the rotary injection unit 33illustrated in FIG. 9 when viewed from the arrow direction of the lineD-D.

As illustrated in FIG. 8 and FIG. 9 , the rotary injection unit 33 hasthe nozzle portion 33 a, a rotary portion 33 b, a bearing portion 33 c,and a body 33 d.

As illustrated in FIG. 8 , the nozzle portion 33 a is a member formed ina cylindrical shape extending along the axis Ra orthogonal to(intersecting) the height direction HD of the paper stack S and having aclosed tip. A plurality of injection holes 33 a 1 that inject air towarda predetermined region including the end face Se in the upstream in thefeeding direction FD of the paper stack S are formed in the side face ofthe nozzle portion 33 a. The plurality of injection holes 33 a 1 arearranged apart from each other at the same position in thecircumferential direction CD about the axis Ra at intervals so as to bealigned along the axis Ra.

As illustrated in FIG. 9 and FIG. 11 , in the nozzle portion 33 a, anopening 33 a 2 communicating between an air supply path 33 d 2 formed inthe body 33 d and an internal space IS of the nozzle portion 33 a isformed in the region of an angle θ2 in the circumferential direction CDat a position facing the air supply path 33 d 2. The angle θ2 ispreferably less than or equal to 180 degrees.

Air injected from the injection hole 33 a 1 is supplied to the internalspace IS of the nozzle portion 33 a when the opening 33 a 2 passes bythe air supply path 33 d 2. The opening 33 a 2 is provided only in arange of the angle θ2 in the circumferential direction CD about the axisRa. Thus, as illustrated in FIG. 10 , the nozzle portion 33 a injectsair from the injection hole 33 a 1 within an injection region JA of anangle less than or equal to 180 degrees on the end face Se side of thepaper stack S in the circumferential direction CD about the axis Ra. Theangle θ1 in the circumferential direction CD of the injection region JAmatches the angle θ2 in which the opening 33 a 2 is formed.

The nozzle portion 33 a is rotated continuously in one direction aboutthe axis Ra, injects air from the injection holes 33 a 1 when theopening 33 a 2 passes by the air supply path 33 d 2 in one turn, anddoes not inject air from the injection holes 33 a 1 when the opening 33a 2 does not pass by the air supply path 33 d 2 in one turn. In such away, the nozzle portion 33 a injects air so as to periodically changethe first injection direction JD1 oriented to a predetermined regionincluding the end face Se in the upstream in the feeding direction FD ofthe paper stack S.

The rotary portion 33 b is a device that is connected to the base endportion of the nozzle portion 33 a and rotates the nozzle portion 33 ain the circumferential direction CD about the axis Ra. A recesses 33 b 1are formed in multiple portions in the circumferential direction CD ofthe rotary portion 33 b. Air from the supply unit 38 is supplied to therecesses 33 b 1 via the air supply path 33 d 1 formed in the body 33 d.The rotary portion 33 b generates driving force for rotation about theaxis Ra by air supplied from the supply unit 38.

The bearing portion 33 c is a member that is fixed to the body 33 d andsupports the side face of the nozzle portion 33 a rotatably about theaxis Ra. A communication hole 33 c 1 communicating between the airsupply path 33 d 2 and the opening 33 a 2 is formed in the bearingportion 33 c. As illustrated in FIG. 9 and FIG. 11 , the communicationhole 33 c 1 is provided at only the position that matches the air supplypath 33 d 2 in the circumferential direction CD about the axis Ra. Thus,the air supply path 33 d 2 and the opening 33 a 2 temporarilycommunicate with each other only when the opening 33 a 2 passes by theposition of the communication hole 33 c 1.

As illustrated in FIG. 9 , the body 33 d is a member that internallyholds the nozzle portion 33 a, the rotary portion 33 b, and the bearingportion 33 c. The body 33 d has the air supply path 33 d 1, the airsupply path 33 d 2, and an accommodation hole 33 d 3. In FIG. 9 , arrowsillustrated on the air supply path 33 d 1 and the air supply path 33 d 2illustrate the flow direction of air guided from the supply unit 38.

The air supply path 33 d 1 is a flow channel through which air suppliedfrom the supply unit 38 is supplied to the rotary portion 33 b. The airsupply path 33 d 2 is a flow channel communicating with theaccommodation hole 33 d 3 and supplied with air from the supply unit 38.The air supply path 33 d 2 guides air supplied from the supply unit 38to the internal space IS of the nozzle portion 33 a. The accommodationhole 33 d 3 is a hole that accommodates the nozzle portion 33 a and thebearing portion 33 c such that a part of the side face in which theinjection hole 33 a 1 is formed protrudes.

Advantages and effects achieved by the sheet folding apparatus 100 ofthe present embodiment described above will be described.

According to the sheet folding apparatus of the present embodiment, theuppermost sheet P of the paper stack S stacked on the stacking unit 10is pulled upward by the suction unit 31 in the upstream in the feedingdirection FD of the sheets P. The injection mechanism 32 of the sheetseparating mechanism 30 then injects air toward a predetermined regionincluding the end face Se in the upstream in the feeding direction FD ofthe paper stack S including the uppermost sheet P of the paper stack 5,and thereby the uppermost sheet P is separated from the remaining sheetsP.

Further, according to the sheet folding apparatus 100 of the presentembodiment, since the rotary injection unit 33 periodically changes thefirst injection direction JD1 oriented to a predetermined region, it ispossible to facilitate separation between the uppermost sheet P andanother sheet P by blowing air to the interface between the uppermostsheet P and another sheet P even when the uppermost sheet P is pulled bythe suction unit 31 with another sheet P being attached thereto. Sincethis causes only the uppermost sheet P to be suitably separated from thepaper stack S in the upstream in the feeding direction FD of the sheetsP, the area in contact with the uppermost sheet P and another sheet Punderside thereof is reduced, and this prevents the uppermost sheet Pand another sheet P underside thereof from being fed together when theuppermost sheet P is fed by the feeding roller 20. As described above,according to the sheet folding apparatus 100 of the present embodiment,it is possible to prevent an increase in manufacturing cost and reliablyseparate and feed the uppermost sheet P of the paper stack S by using asimple mechanism.

Further, according to the sheet folding apparatus 100 of the presentembodiment, it is possible to periodically change, in the heightdirection HD of the paper stack S, the first injection direction JD1 ofair directed to a predetermined region of the end face Se in theupstream in the feeding direction FD of the paper stack S by using arelatively simple structure in which the nozzle portion 33 a is rotatedin a constant direction about the axis Ra orthogonal to (intersecting)the height direction HD of the paper stack S by the rotary portion 33 b.Further, according to the sheet folding apparatus 100 of the presentembodiment, it is possible to facilitate separation between theuppermost sheet P and another sheet P by blowing air to the interfacebetween the uppermost sheet P and another sheet P even when theuppermost sheet P is pulled by the suction unit 31 with another sheet Pbeing attached to the uppermost sheet P.

Further, according to the sheet folding apparatus 100 of the presentembodiment, since air is injected from the injection hole 33 a 1 withinan injection region JA of an angle less than or equal to 180 degrees onthe end face Se side of the paper stack S, it is possible to suitablyprevent air from being injected in a region on the end face Se side ofthe paper stack S to which no air is injected.

Further, according to the sheet folding apparatus 100 of the presentembodiment, air is supplied to the internal space IS of the nozzleportion 33 a from the air supply path 33 d 2 when the opening 33 a 2passes by a position facing the air supply path 33 d 2, and the air isinjected from the injection hole 33 a 1 by supplying air from the supplyunit 38 to the air supply path 33 d 2. Since the opening 33 a 2 isformed in a region of an angle less than or equal to 180 degrees in thecircumferential direction CD on the side face of the nozzle portion 33 aat a position facing the air supply path 33 d 2, a period in which airis supplied from the air supply path 33 d 2 to the internal space IS anda period in which no air is supplied from the air supply path 33 d 2 tothe internal space IS are periodically repeated in accordance with therotation of the nozzle portion 33 a. This makes it possible toperiodically change the first injection direction JD1 of the airdirected to the predetermined region.

Further, according to the sheet folding apparatus 100 of the presentembodiment, it is possible to obtain driving force for driving therotary portion 33 b by using the air supplied from the supply unit 38through the air supply path 33 d 1 without using a dedicated device forgenerating driving force for driving the rotary portion 33 b.

Further, according to the sheet folding apparatus 100 of the presentembodiment, the sheet folding apparatus 100 has the fixed injection unit34 configured to fix the second injection direction JD2 oriented to thepredetermined region and inject air. Thus, while facilitating separationbetween the uppermost sheet P and another sheet P by the rotaryinjection unit 33, it is possible to ensure a sufficient volume of airto be blown to the downstream in the feeding direction FD of the sheetsP along the second injection direction JD2 by the fixed injection unit34 and reliably blow the air to a gap formed between the sheets P.

Second Embodiment

Next, a sheet folding apparatus 100A according to the second embodimentof the present disclosure will be described with reference to thedrawings. The present embodiment is a modified example to the firstembodiment, which is assumed to be the same as the first embodimentunless otherwise specified below, and the description thereof will beomitted below. FIG. 12 is a perspective view illustrating a feedingroller 20 and a sheet separating mechanism 30A of the sheet foldingapparatus 100A according to the second embodiment of the presentdisclosure. FIG. 13 is a diagram of the sheet separating mechanism 30Aillustrated in FIG. 12 when viewed from the feeding roller 20 side,which illustrates a state before the suction unit 31 pulls a sheet Pupwards.

As illustrated in FIG. 12 and FIG. 13 , in the sheet folding apparatus100 according to the first embodiment, the pair of rotary injectionunits 33 of the injection mechanism 32 are fixed to the body 30 a of thesheet separating mechanism 30. In contrast, in the sheet foldingapparatus 100A according to the present embodiment, the pair of rotaryinjection units 33 of the injection mechanism 32 are not fixed to thebody 30 a and arranged at positions separate from the body 30 a alongthe width direction WD by the connection portion 37. The positions inthe width direction WD of the pair of rotary injection units 33 relativeto the connection portion 37 can be adjusted to any positions.

Note that, while the injection mechanism 32 of the present embodimentdoes not have the pair of fixed injection units 34 of the firstembodiment as illustrated in FIG. 12 and FIG. 13 , other forms may beemployed. For example, the fixed injection unit 34 may be installedbetween the rotary injection units 33 at two positions on the left andright in the width direction WD and the pressing portion 36. Further,for example, the fixed injection unit 34 may be installed between therotary injection units 33 at two positions on the left and right in thewidth direction WD and the suction unit 31.

According to the sheet folding apparatus 100 of the present embodiment,since, the pair of rotary injection units 33 of the injection mechanism32 are not fixed to the body 30 a and arranged at positions separatefrom the body 30 a along the width direction WD by the connectionportion 37, even if printing on the sheet P or other factors make itdifficult to separate the uppermost sheet from other sheet P at theposition which is separated along the width direction WD from the body30 a, the uppermost sheet P can be properly separated from other sheetP.

Third Embodiment

Next, a sheet folding apparatus 100A according to the third embodimentof the present disclosure will be described with reference to thedrawings. The present embodiment is a modified example to the firstembodiment, which is assumed to be the same as the first embodimentunless otherwise specified below, and the description thereof will beomitted below. FIG. 14 is a perspective view of a rotary injection unit33B of the third embodiment of the present disclosure. FIG. 15 is apartial sectional view of the rotary injection unit 33B of the thirdembodiment of the present disclosure.

The rotary injection unit 33 of the first embodiment rotates the nozzleportion 33 a about the axis Ra by supplying air from the supply unit 38to the rotary portion 33 b connected to the nozzle portion 33 a. Incontrast, the rotary injection unit 33B of the present embodimentrotates the nozzle portion 33 a about the axis Ra by driving force of adriving motor 33 e.

The driving motor 33 e is connected to the base end portion of thenozzle portion 33 a and is a device for rotating the nozzle portion 33 ain the circumferential direction CD about the axis Ra. The driving motor33 e generates driving force for rotating the nozzle portion 33 a aboutthe axis Ra.

The nozzle portion 33 a is rotated continuously in one direction aboutthe axis Ra, injects air from the injection holes 33 a 1 when theopening 33 a 2 passes by the air supply path 33 d 2 in one turn, anddoes not inject air from the injection holes 33 a 1 when the opening 33a 2 does not pass by the air supply path 33 d 2 in one turn. The nozzleportion 33 a injects air so as to periodically change the firstinjection direction JD1 (see FIG. 10 ) oriented to a predeterminedregion including the end face Se in the upstream in the feedingdirection FD of the paper stack S.

According to the rotary injection unit 33B of the present embodiment, itis possible to rotate the nozzle portion 33 a about the axis Ra bydriving force generated by the driving motor 33 e and inject air so asto periodically change the first injection direction JD1 oriented to apredetermined region including the end face Se in the upstream in thefeeding direction FD of the paper stack S.

What is claimed is:
 1. A sheet feeding apparatus comprising: a stackingunit configured to be stacked with a paper stack including a pluralityof sheets; a feeding unit configured to come into contact with a surfaceof the uppermost sheet of the paper stack and feed the uppermost sheetin a feeding direction; and a sheet separating mechanism configured toseparate the uppermost sheet of the paper stack from the remainingsheets, wherein the sheet separating mechanism comprises a suction unitconfigured to suck and pull the uppermost sheet of the paper stackupward in upstream in the feeding direction, and an injection mechanismconfigured to separate the uppermost sheet from the remaining sheets bya first injection unit configured to inject air so as to change a firstinjection direction oriented to a predetermined region including an endface in upstream in the feeding direction of the paper stack includingthe uppermost sheet of the paper stack.
 2. The sheet feeding apparatusaccording to claim 1, wherein the first injection unit comprises anozzle portion that is formed in a cylindrical shape extending along anaxis intersecting the height direction of the paper stack and having aclosed tip and has an injection hole for injecting air toward thepredetermined region formed in a side face of the nozzle portion, and arotary portion configured to rotate the nozzle portion in apredetermined direction about the axis, and wherein air injected fromthe injection hole is supplied to an internal space of the nozzleportion.
 3. The sheet feeding apparatus according to claim 2, whereinthe nozzle portion injects air from the injection hole within aninjection region of an angle less than or equal to 180 degrees on theend face side of the paper stack in a circumferential direction aboutthe axis.
 4. The sheet feeding apparatus according to claim 3, whereinthe first injection unit has a body that holds the nozzle portion,wherein the body has an accommodation hole and a supply path, theaccommodation hole accommodating the nozzle portion such that a part ofthe side face in which the injection hole is formed protrudes, and thesupply path communicating with the accommodation hole and externallysupplied with air, and wherein in the nozzle portion, an openingcommunicating between the supply path and the internal space within aregion of an angle less than or equal to 180 degrees in thecircumferential direction is formed at a position facing the supply pathof the side face.
 5. The sheet feeding apparatus according to claim 2,wherein the rotary portion generates driving force for rotation aboutthe axis by externally supplied air.
 6. The sheet feeding apparatusaccording to claim 1, wherein the sheet separating mechanism has asecond injection unit configured to fix a second injection directionoriented to the predetermined region and inject air.
 7. A sheetseparating apparatus configured to inject air toward a predeterminedregion of an end face of a paper stack including a plurality of sheetsto separate the sheets from each other, the sheet separating apparatuscomprising: a nozzle portion that is formed in a cylindrical shapeextending along an axis intersecting the height direction of the paperstack and having a closed tip and has an injection hole for injectingair toward the predetermined region formed in a side face of the nozzleportion; and a rotary portion configured to rotate the nozzle portion ina predetermined direction about the axis, wherein air injected from theinjection hole is supplied to an internal space of the nozzle portion.8. The sheet separating apparatus according to claim 7, wherein thenozzle portion injects the air from the injection hole within aninjection region of an angle less than or equal to 180 degrees on theend face side of the paper stack in a circumferential direction aboutthe axis.
 9. The sheet separating apparatus according to claim 8 furthercomprising a body that holds the nozzle portion, wherein the body has anaccommodation hole and a supply path, the accommodation holeaccommodating the nozzle portion such that a part of the side face inwhich the injection hole is formed protrudes, and the supply pathcommunicating with the accommodation hole and externally supplied withair, and wherein in the nozzle portion, an opening communicating betweenthe supply path and the internal space within a region of an angle lessthan or equal to 180 degrees in the circumferential direction is formedat a position facing the supply path of the side face.
 10. The sheetseparating apparatus according to claim 7, wherein the rotary portiongenerates driving force for rotation about the axis by externallysupplied air.